Zoo researchers keep watch on expectant mother Rose-Tu

Oregon Zoo staffers have started an informal office pool predicting the birth date, and researchers are keeping track of Rose-Tus movements and vital signs, trying to pinpoint the date that the new elephant will be born.

Rose-Tu is in her 21st month of pregnancy. Asian elephants have a 22-month gestation period, the longest of any mammal on the planet.

Elephant pregnancy is long and the end point is difficult to predict more than a few days in advance, said zoo research associate Heather Velonis, a graduate student in biology at Portland State University. But if we can identify specific, predictable behaviors that indicate when an elephant will give birth, we might be able to have two weeks notice instead of two days.

Velonis is working with zoo conservation research associate Karen Lewis and zoo volunteers, who are observing Rose-Tu in the weeks leading up to birth, looking for behavioral clues to a possible birth date.

Velonis and observers are collecting data for 30 minutes at a time, four times a day, seven days a week, based on an ethogram  a checklist of specific behaviors, such as how Rose-Tu interacts with others in her herd or how much water she drinks.

Leader in elephant births

Lewis began the study in 2008 when Rose-Tu was pregnant with Samudra. Researchers are also working with the Taronga Zoo in Sydney, Australia, where three elephants have given birth since 2008. Velonis plans to catalog the results of the five births for her masters thesis and for publication in a scientific journal.

The Oregon Zoo has had more than two dozen elephant births since the early 1960s. The zoos most famous elephant, Packy, was born in 1962  the first successful elephant birth in the Western Hemisphere in nearly 44 years.

Weve come a long way, Lewis said. When Packy was born, nobody knew how long an elephant pregnancy lasted or what signs to look for. The zoos veterinarian at the time, Matthew Maberry, spent three months sleeping in the elephant house.

The Oregon Zoo is recognized worldwide for its successful breeding program for Asian elephants, which has spanned 50 years. Rose-Tus mother, Me-Tu, was the second elephant born at the zoo (just months after Packy in 1962), and her grandmother, Rosy, was the first elephant ever to live in Oregon.

Asian elephants are considered highly endangered in their range countries, threatened by habitat loss and conflict with humans. It is estimated that only 40,000 to 50,000 remain in fragmented populations from India to Borneo.